False-twist spindle

ABSTRACT

A SYSTEM FOR TWISTING A YARN BY A TUBULAR MEMBER ADAPTED TO BE ROTATED ABOUT ITS LONGITUDINAL AXIS, THE TUBULAR MEMBER HAVING AT LEAST ONE LONGITUDINAL BORE THROUGH WHICH THE YARN IS FED WHILE IT IS TWISTED, THE TUBULAR MEMBER ALSO HAVING A PAIR OF LATERAL PASSAGEWAYS WHICH COMMUNICATE WITH THE LONGITUDINAL BORE AND WHICH ARE DISPOSED SYMMETRICALLY ABOUT THE LONGITUDINAL AXIS.

Feb. 2, 1971 H. CROUZET 3,559,392 "FALSE-TWIST SPINDLE Filed May '2, 1968 INVENTOR. HEN RI CROUZET his ATTORNEYS.

United States Patent 3,559,392 FALSE-TWIST SPINDLE Henri Crouzet, Rue Cuvier, Roanne, Loire, France Filed May 7, 1968, Ser. No. 727,215 Int. Cl. D01h 7/92; D02g 1/06 US. Cl. 57-77.3 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates to apparatus for twisting a filament such as a thread or a yarn at very high speed and, more particularly, to new and improved false-twist tubes or spindles adapted to be driven at very high speed.

As is well known in the art, stretch fabrics are woven or knitted from yarn having a permanent curl. A falsetwist apparatus is utilized to attain the desired curl. The yarn, which is generally a thermoplastic synthetic fiber, is first twisted by the false-twist apparatus, and by the application of heat, for example, this twist is permanently set in the yarn. The yarn is then untwisted as it leaves the false-twist apparatus and is wound on a bobbin ready for weaving or knitting. Because of the permanent set in the untwisted yarn, which causes it to tend to return to its twisted condition, the desired stretch property is obtained in the woven fabric. In particular, this untwisting of the yarn which has been heated to be fixed in its temporarily twisted condition imparts a texturization to the yarn which is characterized by a three-dimensional curling, so that the yarn is in a high-bulk state. This permits the uncurling of the yarn to result in a elastic elongation which can considerably exceed 200%. By elastic uncurling elongation is means the elongation produced by a tension sufiicient to straighten out the yarn without any stretching of the yarn itself. When this tension is removed, the yarn returns rapidly to the contracted and three-dimensionally curled condition.

The false twist is applied to the yarn by a rotating spindle or tube through which the yarn passes, the spindle being constructed so as to engage the yarn as it passes therethrough. It is apparent that the rate at which the yarn may be fed through the false-twist tube is proportional to, and limited by, the rotational speed of this tube, if the degree of false twist imparted to the yarn is to be maintained. Accordingly, considerable effort has been expended in the development of false-twist apparatus to increase the speed at which the spindles may be driven.

At first the spindles were driven by belts at speeds of 10,000 to 15,000 revolutions per minute. Then the spindles were mounted on ball bearings, which enables an increase of speed to 120,000 revolutions per minute. By means of the pneumatic turbine, speeds of 200,000 to 250,000 revolutions per minute were attained.

Similar speeds were obtained more easily by means of the so-called magnetic spindles, in which the false-twist tubes are applied magnetically against the two or more rotating driving members. Preferred embodiments of magnetic false-twist apparatus are disclosed in my Pat. No. 3,232,037 which issued Feb. 1, 1966 and is entitled False- Twist Spindle. Here the false-twist tube, constructed of a magnetizable material, is retained against two coaxial driving disks by the poles of a permanent magnet, the poles of the magnet being disposed externally of the driving disks.

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As discussed above, the yarn travels through the falsetwist tube and is engaged by an element secured to or integral with such tube, so that rotation of the tube imparts the false twist to the yarn, and the yarn is untwisted downstream of the false-twist tube.

Conventional false-twist include an element such as a transverse pin disposed at the exit end of the tube, the yarn being looped around the pin. In such an arrangement the yarn changes its direction very rapidly as it passes around the pin. This limits the speed at which the thread may be drawn through the tube due to the friction between the yarn and the pin. Also, any wobble of the tube at very high rotational speeds aggravates these effects since the yarn-engaging transverse pin is disposed at one end of the rotating tube. Furthermore, the wobbling of the tube itself may be aggravated by the engagement of the yarn with the rotating tube at one end thereof.

Other prior art false-twist tubes cannot be rotated at extremely high speeds due to non-symmetry about the longitudinal axis and/or are limited by the heat that is developed at such rotational speeds.

Accordingly, it is an object of this invention to provide new and improved false-twist spindles which effectively overcome the above-mentioned disadvantages of the prior art.

Another object of the invention is to provide false-twist spindles which are capable of being rotated at 1,000,000 revolutions per minute or even faster.

These and other objects of the invention are attained by providing a false-twist spindle or tube of magnetizable material which is formed with yarn-engaging lateral passageways which are disposed symmetrically about the longitudinal axis of the tube at the axial center thereof.

Further objects and advantages of this invention will be apparent from the following detailed description in conjunction with the accompanying drawings showing preferred embodiments, in which:

FIG. 1 is an elevational view, in section, of a typical false-twist spindle in accordance with the invention;

FIG. 2 is an elevational view looking from the right side of the apparatus of FIG. 1;

FIG. 3 is an elevational view, in section, of another embodiment of a false-twist spindle according to the invention;

FIG. 4 is an elevational view looking from the right side of the apparatus of FIG. 3;-

FIG. 5 is an elevational view, in section, of still another embodiment of false-twist apparatus according to the invention; and

FIG. 6 is an elevational view, in section, of yet another embodiment of a false-twist apparatus according to the invention.

In the typical embodiment of the invention shown in FIGS. 1 and 2, a false-twist or spindle 10 made of a magnetizable material such as chrome steel is formed with a pair of longitudinally spaced, coaxial bores 11 and 12, each of the bores communicating with a different end of the tube. The edges of the orifices of the bores 11 and 12 are beveled at 13 and 14, respectively, to facilitate the passage of the yarn therethrough. The lateral wall 15 of the tube is perforated by a pair of lateral passageways or bores 16 and 17 which communicate with the upper end of the lower bore 11. The passageways 16 and 17 diverge upwardly from the bore 11 and are symmetrically disposed about the longitudinal axis of the tube 10, the axes of the passageways 16 and 17 lying in a plane which includes the longitudinal axis of the tube.

Similarly, the lateral wall 15 perforated by a pair of lateral passageways 19 and 20 which diverge downwardly from the lower end of the upper bore 12, the passageways 19 and 20 being disposed symmetrically about the longitudinal axis of the tube, and the axes of these passageways lying in the plane including the longitudinal axis of the tube and the axes of the passageways 16 and 17. In addition, the lateral passageways are spaced equidistant from the center of the false-twist tube.

The interior surfaces of the lateral passageways are preferably highly polished, as is the exterior surface of the spindle between these passageways. Also, the edges of the orifices of the passageways are preferably rounded. If desired, small bushings could be set in the passageways, the bushings being of any suitable very hard material, such as a sintered material.

The yarn F to be false twisted is fed from the bottom, for example, through the bore 11 and out through either of the lower passageways 16 and 17, after which it runs around the outside of the tube in a helical half-circle to the one of the upper passageways 19 and which is on the opposite side of the longitudinal axis of the tube. The yarn then passes through that upper passageway and up through the upper bore 12 to other elements of the falsetwist apparatus (not shown), which do not form a part of the present invention.

Thus, the yarn could exit through the passageway 17 and reenter through the passageway 19, or could exit through the passageway 16 and reenter through the passageway 20. The unused pair of passageways insure that the tube is dynamically balanced. In addition, some ventilation is provided by the two transverse paths including the passageways 19 and 20, and 16 and 17. If desired, helical grooves could be formed in the exterior of the tube between the passageways 17 and 19, and the passage ways 16 and 20.

By longitudinally spacing the bores 11 and 12, rather than providing one longitudinal bore running the entire length of the false-twist tube, the mass of the tube in the central portion 18 thereof is correspondingly increased. This improves the dynamic balance of the tube and reduces its tendency to wobble at very high rotational speeds.

By guiding the yarn over the helical half-turn b tween opposite ones of the upper passageways 19 and 20 and the lower passageways 16 and 17, the yarn is properly engaged by the spindle to put the desired false-twist in the yarn, yet the tube may be driven at rotational speeds up to 1,000,000 revolutions per minute, or even more, thus enabling the yarn to be fed through the tube at considerably greater linear speeds than is possible with the conventional spindles known to the art.

FIGS. 3 and 4 illustrate another embodiment of the invention. Corresponding portions of the two embodiments carry the same reference numerals, primes being added in FIGS. 3 and 4. The false-twist tube also includes a pair of longitudinally spaced, coaxial bores 11' and 12' which communicate with the lateral symmetrical passageways 16' and 17', and 19' and 20', respectively. In addition, the false-twist tube 25 includes a transverse bore 27, which is disposed midway between the ends of the tube, the axis of the bore 27 being preferably perpendicular to the plane including the axes of the passageways 16', 17', 19' and 20. The outer edges of the bore 27 are chamfered at 28 and 29, thereby reducing the outside path of the yarn between the lower passageway 16' or 17 and the corresponding upper passageway 20' or 19. This minimizes any adverse effect that the exposed length of yarn between the lateral passageways might have on the dynamic balance of the false-twist tube. Furthermore, the transverse bore 27 insures that the false-twist tube is sufficiently ventilated to dissipate the heat generated when the tube is rotated at extremely high rotational speeds.

FIG. 5 illustrates another embodiment of a false-twi t spindle according to the invention. The false-twist tube 30 is made of a suitable magnetizable material and is formed with a pair of longitudinally spaced, coaxial bores 32 and 33 and a pair of laterally extending annular flanges or shoulders 34 and 35, the shoulders being equally spaced from the adjacent ends of the false-twist tube. The lateral wall of the tube is perforated through the shoulder 34 by a pair of lateral passageways 37 and 38 which diverge upwardly from the upper end of the lower bore 32, the passageways 37 and 38 communicating the bore 32 with a pair of orifices 39 and 40, respectively, disposed in the upper surface 42 of the shoulder 34 adjacent the central lateral cylindrical surface 44 of the false-twist spindle.

Similarly, the lateral wall of the tube is perforated through the shoulder 35 with a pair of lateral passageways 47 and 48 which extend downwardly and outwardly from the lower end of the upper bore 33 to a pair of orifices 49 and 50 disposed in the lower surface 52 of the upper shoulder 35, the orifices 49 and 50 being adjacent the central lateral cylindrical surface 44.

As in the previous embodiments, the upper passageways 47 and 48 and the lower passageways 37 and 38 are symmetrical about the longitudinal axis of the tube 30, and the axes of these four passageways lie in a single plane which includes the longitudinal axis of the tube. Also, a central transverse bore 55 is provided to promote the ventilation of the tube, the axis of this bore being preferably perpendicular to the plane containing the axes of the lateral passageways. If desired, the central lateral surface 44 may be chamfered'at the orifices of the transverse bore 55 in order to reduce the exposed path of the yarn along the surface 44 between the lower passageways 37 and 38 and the upper passageways 47 and 48.

As before, the yarn to be false-twisted travels upwardly through the lower bore 32 from which it exits by either of the lower lateral passageways 37 and 38. The yarn then follows a semi-circular helical path around the central lateral surface 44 and reenters the tube through the one of the upper lateral passageways 47 and 48 which is disposed on the opposite side of the tube from the lower passageway by which the yarn exits from the lower bore 32. The yarn then passes from that upper lateral passageway through the upper bore 33 and to the other elements (not shown) of the false-twist apparatus.

The purpose of the lateral shoulders or flanges 34 and 35 is to improve the dynamic balance of the false-twist tube 30 by increasing the mass of the tube in the central portion thereof, thereby minimizing any tendency of the tube to wobble when it is driven at extremely high rotational speeds.

Still another embodiment of the invention is illustrated in FIG. 6. Here the false-twist spindle 60 includes a central cylindrical tube 62 which is formed with three coaxial longitudinal bores 63, 64 and 65, and two spaced transverse bores 67 and 68, the axes of the transverse bores 67 and 68 being parallel with each other and perpendicular to the longitudinal axis of the tube 62. In addition, a central transverse bore 70 is provided, the axis of the bore 70 being perpendicular to the plane containing the axes of the tranverse bores 67 and 68.

Mounted in each of the transverse bores 67 and 68 is a corresponding one of a pair of bushings 71 and 72 having longitudinal bores 73 and 74, respectively, passing therethrough, the outer edges of the bores 73 and 74 being rounded at least along the portion thereof closest to the central bore 70, as illustrated at 75. Each of the bushings 71 and 72 is formed with a lateral passageway 76 and 77, respectively, the passageways 76 and 77 being in registry with the longitudinal bores 63 and 65, respectively. The inner edges of the passageways 76 and 77 are preferably rounded as illustrated at 78.

A casing or collar 80 is secured to the tube 62 by any suitable means such as press-fit, the tube 62 being received in a longitudinal bore 82 of the casing 80. The casing 80 is disposed equidistant from the ends of the tube 62 and is provided with a pair of lower lateral passageways 84 and 85 which diverge upwardly from the longitudinal bore 82 to the outer lateral surface 86 of the casing 80. The casing 80 also has a pair of upper lateral passageways 88 and 89 which diverge downwardly from the longitudinal bore 82 to the outer lateral surface 86. The axes of the passageways 84, 85, 88 and 89 all lie in a single plane which includes the longitudinal axis of the tube 62. The inner orifices 91 and 92 of the passageways 84 and 85, respectively, are in registry with the transverse bore 67 of the tube 62, and the inner orifices 94 and 95 of the passageways 88 and 89, respectively, are in registry with the transverse bore 68. Also, the casing has a pair of central, transverse, spaced, coaxial bores 97 which are in registry with the transverse :bore 70 of the tube 62.

As before, the yarn to be false-twisted travels up through the lower bore 63 and the passageway 76 and the bore 73 of the bushing 71, and thereafter through one of the lower lateral passageways 84 and 85 of the collar 80. The yarn then follows a semi-circular helical path around the outside lateral surface 86 of the collar, and then through the particular one of the upper lateral passageways 88 and 89 which is on the opposite side of the longitudinal bore 64 from the particular one of the lower lateral passageways 84 and 85 which the yarn has traversed. From the upper lateral passageway the yarn passes through the bore 74 and the passageway 77 of the bushing 72 and thereafter through the upper longitudinal bore 65 to the other elements (not shown) of the false-twist apparatus.

The casing 80 improves the dynamic balance of the spindle 60 by increasing the mass of the spindle in the central portion thereof, and the transverse central passageway formed by the bores 70 and 97 improves the ventilation of the spindle and thus promotes the dissipation of heat which is generated at extremely high rotational speeds.

The above-described novel false-twist tubes are preferably employed with magnetic false-twist apparatus such as that disclosed in my above-mentioned Pat. No. 3,232,- 037. In that false-twist apparatus the poles of the permanent magnet which retain the false-twist tube against the coaxial driving disks are disposed externally of the driving disks. In such an arrangement, the ends of the false-twist tube would preferably extend beyond the coaxial driving disks only by the extent required to ensure a sutficient path for the magnetic flux between the poles of the permanent magnet and the false-twist tube. It is to be understood, however, that the false-twist tubes according to the present invention may also be used in false-twist apparatus in which one or more poles of the permanent magnet are inside of the driving disks, and the false-twist tubes illustrated in FIGS. and 6 operate especially well in this latter type of false-twist apparatus, because of the enlarged central portion thereof. The present false-twist tubes may also be used to advantage with the false-twist apparatus disclosed in my application entitled False-Twist Apparatus filed concurrently herewith. In addition, the novel false-twist tubes according to the present invention could be employed in false-twist apparatus in which the tube is mechanically, as contrasted with magnetically, suspended, if desired.

Although this invention has been described with reference to the foregoing specific embodi.nents, it will be understood that various substitutions, changes and modifications in the form and details of the apparatus illustrated and its manner of employment may be made by those skilled in the art without departing from the spirit of the invention. For example, the exposed semicircular helical path of the yarn around the central outside surface of the spindle could be omitted by passing the yarn directly from one of the lower lateral passageways to the closer of the two upper lateral pasageways. In such an arrangement, however, the yarn would be less positively gripped by the spindle, so that the ratio of the longitudinal speed of the yarn to the rotational speed of the spindle would have to be reduced accordingly if the same degree of false twist were to be attained. Also, one pair of lateral passageways could be disposed in a plane at angle to the plane containing the other pair of lateral passageways. All such variations and modifications, therefore, are included in the intended scope of the invention as defined by the following claims.

I claim:

1. Apparatus for twisting a yarn comprising a tubular member adapted to be rotated at extremely high speeds about its longitudinal axis by a driving mechanism, the tubular member having at least one longitudinal bore through which the yarn is adapted to be fed while it is being twisted, the tubular member also having a first pair of lateral passageways and a second pair of lateral passageways communicating with the longitudinal bore and adapted to receive the yarn to be twisted and to engage the yarn so as to twist it, the first and second pairs of passageways being axially spaced from each other and equidistant from the longitudinal center of the tubular member, the lateral passageways of each pair being disposed symmetrically about the longitudinal axis of the tubular member and diverging outwardly toward the passageways of the other pair, the tubular member being formed so as to be dynamically balanced about its longitudinal axis.

2. Apparatus according to claim 1 wherein the axes of the lateral passageways lie in a single plane which includes the longitudinal axis of the tubular member, whereby the yarn to be twisted may be fed from one of the first pair of lateral passageways to the diametrically opposite one of the second pair of lateral passageways so that the yarn runs around the outside of the tubular member between the first and second pairs of lateral passageways in a helical half-turn.

3. Apparatus according to claim 1 wherein the tubular member has a transverse bore for ventilating the tubular member to dissipate the heat generated when it is rotated at extremely high rotational speeds, the transverse bore being substantially perpendicular to the longitudinal axis and equidistant from the ends of the tubular member.

4. Apparatus according to claim 3 wherein the axes of the lateral passageways lie in a single plane, and the axis of the transverse bore is perpendicular to the plane of the lateral passageways.

5. Apparatus acording to claim 1 wherein the tubular member is enlarged at the central portion thereof.

6. Apparatus according to claim 1 wherein the tubular member has a pair of laterally extending shoulders equidistant from the longitudinal center thereof.

7. Apparatus according to claim 1 wherein the tubular member has a pair of axially spaced longitudinal bores, each of the two pairs of passageways communicating with a different one of the longitudinal bores.

'8. Apparatus according to claim 1 wherein the axes of one pair of lateral passageways lie in a first plane which includes the longitudinal axis of the tubular member and the axes of the other pair of lateral passageways lie in a second plane which includes the longitudinal axis of the tubular member, the first and second planes being angularly offset from each other.

9. Apparatus for twisting a yarn comprising a tubular member adapted to be rotated at extremely high speeds about its longitudinal axis by a driving mechanism and adapted to be supported in driving engagement with the driving mechanism by a magnetic device, the tubular member being constructed at least partially of magnetizable material and having at least one longitudinal bore through which the yarn is adapted to be fed while it is being twisted, the tubular member also having a first group of exit lateral passageways and a second group of reentry lateral passageways communicating with the longitudinal bore and adapted to receive the yarn to be twisted and to engage the yarn so as to twist it, the first and second groups of lateral passageways being axially spaced from each other and equidistant from the longitudinal center of the tubular member, the lateral passageways of each group being disposed symmetrically FOREIGN PATENTS about the longitudinal axis of the tubular member, the 1,263,019 4/1961 France 57 77 3 tubular member being fermed so as to be dynamically 595,004 3/1934 Germany 57 77 3 balanced about its l0ng1tud1nal axis. 752 52 7 195 Great B i i 57 77 3 5 783,493 9/1957 Great Britain 5777.3

References Cited UNITED STATES PATENTS JOHN PETRAKES, Primary Examiner 2,821,062 1/1958 Boillat et a1. 57-77.33 U,S C1 X,R

3,363,409 1/1968 Schwabe et al. 57-77.3 6 57 77 33, 77.45 

